ColdFusion ORM - Part II

Copyright 2009 Adobe Systems Incorporated. All rights reserved. Adobe confidential. 1
ColdFusion-ORM - II
Rupesh Kumar
Sr. Computer Scientist
Blog: www.rupeshk.org

®
Agenda
 Relationships (contd from last session)
 Application settings
 Advanced Mapping
 What happens internally
 Transaction & concurrency control
 Caching & optimization
 Event Handling
 Q & A

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Address.cfc
<cfproperty name="EmployeeObj" fieldtype="one-to-one" cfc="employees"
fkcolumn="EmployeeID">
Employees.cfc
<cfproperty name="addressObj" fieldtype="one-to-one" cfc="address"
mappedby="EmployeeObj">
3
Mapping One-to-One relationship
EMPLOYEES
EmployeeID(PK)
LastName
FirstName
Title
ADDRESSES
AddressID(PK)
HouseNumber
Street
City
State
Country
EmployeeID
1
1

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EMPLOYEES
EmployeeID(PK)
LastName
FirstName
Title
Mapping Many-to-Many relationship
<cfproperty name=“Territories” fieldtype=“many-to-many” cfc=“territories”
linktable=“employeeterritories” fkcolumn=“EmployeeID”
inversejoincolumn=“TerritoryID”>
TERRITORIES
TerritoryID(PK)
TerritoryDescription
n n
EMPLOYEETERRITORIES
EmployeeID(PK)
TerritoryID(PK)

ColdFusion-ORM
APPLICATION
SETTINGS

®
Ormenabled – Specifies whether ORM should be used for the
ColdFusion application
Eg: <cfset this.ormenabled = true>
ORMSettings – The struct that defines all the ORM settings
Eg: <cfset this.ormsettings = {datasource=“employees”}>
datasource – Defines the default datasource for the
application.
Eg: <cfset this.datasource = “employees” >
66
Application Level Settings

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cfclocation – Specifies the directory (or array of directories) to
search for persistent CFCs.
Eg: <cfset this.ormsettings = {cfclocation=“/empSys/model/”}>
savemapping – Specifies whether the generated Hibernate
mapping file has to be saved to disk.
Eg: <cfset this.ormsettings = {savemapping=“true”}>
logSQL – Specifies whether the SQL queries that are executed
by ORM will be logged.
Eg: <cfset this.ormsettings = {logSQL=“true”}>
77
Application Level Settings – ormsettings

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datasource– Specifies the datasource to be used by ORM.
Eg: <cfset this.ormsettings = {datasource=“employees”}>
secondaryCacheEnabled – Specifies whether the secondary
cache will be enabled for ORM.
Eg: <cfset this.ormsettings = {secondarycacheEnabled=“true”}>
eventHandling – Specifies whether the event handling is
enabled for ORM.
Eg: <cfset this.ormsettings = {eventHandling=“true”}>
Many More…
88
Application Level Settings – ormsettings

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dbCreate – Specifies whether tables should be auto-generated at
application startup.
 Update – create new or update if table exists
 Dropcreate – drop and then create table
 None* – do nothing
NamingStrategy – Specifies the method used to generate the
table/column names.
 Default* – CFC names matches table/column name
 Smart – CFC “OrderProduct” is “ORDER_PRODUCT” in db
 Your own CFC – implements cfide.orm.INamingStrategy
SqlScript – Specifies the sql script file that will be run after the
tables are created. It can be used to initialize the DB.
99
Ormsettings for Auto-generating tables

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Advanced Mapping
 Collection Mapping
 Embedded Mapping
 Inheritance Mapping
 Join Mapping

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Collection Mapping
 Similar to 1:n relationship
 Useful when target table need not be mapped as persistent CFC
 Just need information from the target table
 Mapping defined similar to 1:n relationship
 Demo

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Embedded Mapping
 One entity with multiple CFC
 A cfproperty refers to another cfc
 Mapping needs to be specified in *.hbm.xml
<hibernate-mapping>
<class name="cfc:Employees" entity-name="employee"
table="Employees">
<id name="ID" type="integer" column="EmployeeID">
<generator class="native"/>
</id>
<component name="Name" class="cfc:cname">
<property name="FirstName" type="string" column="FirstName"/>
<property name="LastName" type="string" column="LastName"/>
</component>
<property name="Title" type="string" column="Title"/>
<property name="BirthDate" type="date" column="BirthDate"/>
<property name="HireDate" type="date" column="HireDate"/>
</class>
</hibernate-mapping>

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Inheritance Mapping
 Three Types
 Table per hierarchy
Payment
+ID
+Amount
+Date
CreditCardPayme
nt
+CardNo
+CardType
ChequePayment
+ChequeNo
+bankName
+City
ID <<PK>>
Amount
Date
PaymentType
(discriminator)
CardNo
CardType
ChequeNo
BankName
City
Payment Table

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Inheritance Mapping
 Three Types
 Table per subclass without discriminator
Payment
+ID
+Amount
+Date
CreditCardPayme
nt
+CardNo
+CardType
ChequePayment
+ChequeNo
+bankName
+City
ID <<PK>>
Amount
Date
Payment Table
PaymentID
CardNo
CardType
CreidtCardPayment Table
PaymentId
ChequeNo
BankName
City
Cheque Payment Table

®
Inheritance Mapping
 Three Types
 Table per subclass without discriminator
 Table per subclass with discriminator
Payment
+ID
+Amount
+Date
CreditCardPayme
nt
+CardNo
+CardType
ChequePayment
+ChequeNo
+bankName
+City
ID <<PK>>
Amount
Date
PaymentType
(discriminator)
Payment Table
PaymentID
CardNo
CardType
CreidtCardPayment Table
PaymentId
ChequeNo
BankName
City
Cheque Payment Table

®
Join Mapping
 Useful when using one CFC for multiple tables
<cfcomponent persistent="true“ table=“employee”>
<cfproperty name="id">
<cfproperty name="name">
<cfproperty name="city"
table="Address” joincolumn="addressId">
<cfproperty name="country"
table="Address“ joincolumn="addressId">
</cfcomponent>

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Application
Start
ORM
Enable
d?
Proceed
with other
activities
false
true
Create/Load
Hibernate
configuration if
specified
Load Hibernate
mapping files
(*.hbmxml)
Search for persistent
CFCs
Generate Hibernate
Mapping for
persistent CFCs
DatabaseInspect
Generate DDL
based on dbcreate
Build Hibernate
Session Factory
Proceed
with other
activities
ORM Initialization

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ORM Session
 Represents a unit of work – typically a transaction
 All the ORM operations happen in a session
 Ensures a single instance of an entity.
 Tracks changes made to the objects
 SQLs are executed when session is flushed
 Typically when the transaction is committed or when the request completes
 Can use ORMFlush to force
 Automatically managed by CF
 In most cases, you don’t need to worry about it
 Provides First Level Caching

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ORM Session Management
New Request
New ORM Session
Call ORMFlush
Close Session
Batch all the operations
Application
Start

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ORM Session Management – Transactions
20
New Request
New ORM Session
Application
Start
Call ORMFlush
Close ORM Session
New ORM Session
Call ORMFlush
Close ORM Session
Batch all the operations

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Object States
 Transient
 Persistent
 Detached
EntityNew()/ new()/
CreateObject
Transient Entity
Persistent Entities
EntitySave()
DB
Detached
Session ends
EntityLoad
ORMExecuteQuery
EnityMerge
EntityDelete
EntitySave
Session

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Concurrency Control
 Optimistic lock for high concurrency
 Update only if the entity is not modified by other thread or externally.
 optimisticlock attribute on cfc
 All
 All properties are included in where clause of update
Update myTbl set col1= newVal, col2= newVal2
where col1= oldVal and col2= oldVal2
 Dirty
 Includes only modified fields in the current session
 Version (default)
 Checks only version or timestamp column
<cfproperty name="lastModified“ fieldtype="timestamp|version“>
 None
 You can also choose the property for dirty check.

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Fetching Strategy
 Immediate fetching
 Fetch target relationship in a separate SQL, immediately
<cfproperty name=“emp" fieldtype="one-to-many" cfc=“order"
fkcolumn=“EMPID“ lazy="false" fetch="select">
 Lazy fetching
 Default strategy, lazy=true
 On demand, fetch related entities
 Lazy = “extra” gets pk of orders and then all order columns from db
 Eager fetching
 Fetch together in a single SQL, fetch=“join”
 Useful for 1:1 frequently used relationships
 Batch fetching
 When fetching relationship, get some more that maybe required later
 Get Addr1 for emp101, plus address for emp102, 103 etc from the table depending on
batch size

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Caching
 Session Level
 Ensures a single instance for a given ID
 EntityLoad fetches data for the first time
 Data is cached for the session
 Next request in the same session will use cached data
 EntyReload re-fetches
 Secondary Level Cache

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Secondary Level Cache
 Caches data across sessions
 In-memory/disk/clustered
 Pluggable cache impls
 Default - EHCache
 Component Caching
 Collection Caching
 Query Caching
Secondary Cache
…

®
Secondary Level caching ...
 Configuration in Application.cfc
 ormsettings.secondarycacheenabled
 ormsettings.Cacheprovider
 JBossCache, OSCache, SwarmCache, Hashtable, DEFAULT - ehcache
 ormsettings.cacheconfig
 Appropriate config file for cache, e.g. ehcache.xml
 In ORM cfc
 “cacheuse” defines caching strategy
 “cahcename” cache region, a bucket for this data
<cfcomponent persistent="true“
cachename=“foo_region" cacheuse="read-only">

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Caching - examples
 Component
 <cfcomponent persistent="true“
cachename=“foo_region" cacheuse="read-only">
 Relationship
 Primary Key of the associated object is cached
 The associated object itself is cached if coded as above
<cfproperty name="arts" fieldtype="one-to-many“
cachename="foo_region" cacheuse="read-write">
 Query data
ORMExecuteQuery("from Art where issold=0", {}, false,
{cacheable=true, cachename=“foo_region"});

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Caching – cacheuse
 Read-only
 Best performance for read only data
 Nonrestrict-read-write
 Use when data is updated occasionally
 Read-write
 Use if your data needs to be updated
 More overhead than the two preceding strategies
 Transactional
 Transactional cache
 Can only be used if the cache provider is transaction aware

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Caching - cleanup
 ORMEvictEntity
ORMEvictEntity("<component_name>", [primarykey])
 ORMEvictCollection
ORMEvictCollection("<component_name>", "<relation_name>",
[primarykey])
 ORMEvictQueries
ORMEvictQueries([cachename])

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Event Handling
 Set ormsettings.eventhandling=“true”
 CFC level
 preinsert and postinsert
 predelete and postdelete
 preupdate and postupdate
 preload and postload
 Application Level
 Set ormsettings.eventhandler=“AppEventHandler.cfc”
 Should implement the CFIDE.orm.IEventHandler interface

Q & A

Thank You !
- rukumar@adobe.com
- http://www.rupeshk.org

ColdFusion ORM - Part II

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